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  • Keeping control of your media in your hands

    13 avril 2011, par

    The vocabulary used on this site and around MediaSPIP in general, aims to avoid reference to Web 2.0 and the companies that profit from media-sharing.
    While using MediaSPIP, you are invited to avoid using words like "Brand", "Cloud" and "Market".
    MediaSPIP is designed to facilitate the sharing of creative media online, while allowing authors to retain complete control of their work.
    MediaSPIP aims to be accessible to as many people as possible and development is based on expanding the (...)

  • Les formats acceptés

    28 janvier 2010, par

    Les commandes suivantes permettent d’avoir des informations sur les formats et codecs gérés par l’installation local de ffmpeg :
    ffmpeg -codecs ffmpeg -formats
    Les format videos acceptés en entrée
    Cette liste est non exhaustive, elle met en exergue les principaux formats utilisés : h264 : H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 m4v : raw MPEG-4 video format flv : Flash Video (FLV) / Sorenson Spark / Sorenson H.263 Theora wmv :
    Les formats vidéos de sortie possibles
    Dans un premier temps on (...)

  • Submit bugs and patches

    13 avril 2011

    Unfortunately a software is never perfect.
    If you think you have found a bug, report it using our ticket system. Please to help us to fix it by providing the following information : the browser you are using, including the exact version as precise an explanation as possible of the problem if possible, the steps taken resulting in the problem a link to the site / page in question
    If you think you have solved the bug, fill in a ticket and attach to it a corrective patch.
    You may also (...)

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  • swscale/aarch64 : use multiply accumulate and shift-right narrow

    9 décembre 2019, par Sebastian Pop
    swscale/aarch64 : use multiply accumulate and shift-right narrow

    This patch rewrites the innermost loop of ff_yuv2planeX_8_neon to avoid zips and
    
horizontal adds by using fused multiply adds. The patch also uses ld1r to load
    
one element and replicate it across all lanes of the vector. The patch also
    
improves the clipping code by removing the shift right instructions and
    
performing the shift with the shift-right narrow instructions.
    

    I see 8% difference on an m6g instance with neoverse-n1 CPUs :
    
$ ffmpeg -nostats -f lavfi -i testsrc2=4k:d=2 -vf bench=start,scale=1024x1024,bench=stop -f null -
    
before : t:0.014015 avg:0.014096 max:0.015018 min:0.013971
    
after :  t:0.012985 avg:0.013013 max:0.013996 min:0.012818
    

    Tested with `make check` on aarch64-linux.
    

    Signed-off-by : Sebastian Pop <spop@amazon.com>
    
Reviewed-by : Clément Bœsch <u@pkh.me>
    
Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
    • [DH] libswscale/aarch64/output.S

  • swscale : aarch64 : Optimize the final summation in the hscale routine

    20 avril 2022, par Martin Storsjö
    swscale : aarch64 : Optimize the final summation in the hscale routine

    Before :                     Cortex A53      A72      A73  Graviton 2  Graviton 3
    
hscale_8_to_15_width8_neon :     8273.0   4602.5   4289.5      2429.7      1629.1
    
hscale_8_to_15_width16_neon :   12405.7   6803.0   6359.0      3549.0      2378.4
    
hscale_8_to_15_width32_neon :   21258.7  11491.7  11469.2      5797.2      3919.6
    
hscale_8_to_15_width40_neon :   25652.0  14173.7  12488.2      6893.5      4810.4
    

    After :
    
hscale_8_to_15_width8_neon :     7633.0   3981.5   3350.2      1980.7      1261.1
    
hscale_8_to_15_width16_neon :   11666.7   5951.0   5512.0      3080.7      2131.4
    
hscale_8_to_15_width32_neon :   20900.7  10733.2   9481.7      5275.2      3862.1
    
hscale_8_to_15_width40_neon :   24826.0  13536.2  11502.0      6397.2      4731.9
    

    Thus, this gives overall a 8-29% speedup for the smaller filter
    
sizes, around 1-8% for the larger filter sizes.
    

    Inspired by a patch by Jonathan Swinney <jswinney@amazon.com>.
    

    Signed-off-by : Martin Storsjö <martin@martin.st>
    • [DH] libswscale/aarch64/hscale.S

  • vp9 : drop support for real (non-emulated) edges

    20 décembre 2013, par Anton Khirnov
    vp9 : drop support for real (non-emulated) edges

    They are not measurably faster on x86, they might be somewhat faster on
    
other platforms due to missing emu edge SIMD, but the gain is not large
    
enough to justify the added complexity.
    • [DH] libavcodec/vp9block.c
    • [DH] tests/fate/vpx.mak

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